CHONDROITIN SULFATE PROTEOGLYCAN DISTRIBUTION IN THE PRIMATE OPTIC-NERVE HEAD

Purpose. To evaluate the presence and distribution of chondroitin and dermatan sulfate-containing proteoglycans in normal human and monkey o ptic nerve heads by light microscopic immunohistochemistry. Methods. M onoclonal antibodies specific for glycosaminoglycan attachment sites r emaining after incubation of tissues with chondroitinase ABC and ACII were used to detect proteoglycans containing unsulfated chondroitin (O S), chondroitin-4 and/or dermatan sulfate (4S), and chondroitin-6 sulf ate (6S) glycosaminoglycans. Results. 4S antibody labeling after chond roitinase ABC was heavily and evenly distributed within the peripapill ary sclera and in the core of laminar beams and optic nerve septa. Pre incubation with chondroitinase AC, which exposes only chondroitin sulf ate attachment sites, diminished labeling intensity in the lamina crib rosa and sclera and almost completely eliminated it in the retrolamina r optic nerve septa. In contrast, 6S antibodies demonstrated a more in termittent linear distribution throughout the laminar beams and optic nerve septa. No qualitative differences were seen between human and mo nkey optic nerve heads.Conclusion. Chondroitin and dermatan sulfate-co ntaining proteoglycans exist throughout the support tissues of the opt ic nerve head. The specific distribution patterns demonstrated by thes e monoclonal antibodies, and, in particular, the unique confinement of one of them to the lamina, indicate the presence of different core pr oteins or different functional glycosaminoglycan side chains that may influence the behavior of the lamina cribrosa.